Random and Binary IO with generic Iteratees. These functions use Handles
for IO operations, and are provided for compatibility. When available,
the File Descriptor based functions are preferred as these wastefully
allocate memory rather than running in constant space.

File enumerators

The (monadic) enumerator of a file Handle. This version enumerates
over the entire contents of a file, in order, unless stopped by
the iteratee. In particular, seeking is not supported.
Data is read into a buffer of the specified size.